PTL-0028 verification guide

This document details the complete positive and negative testing matrix for PTL-0028, executed and verified inside Cisco Packet Tracer 9.0.1.

1. Positive Verification (POS)#

POS-01: Point-to-Point WAN Link Reachability#

On Edge-R1 privileged EXEC mode, verify reachability across both WAN segments:

Edge-R1# ping 10.1.1.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 0/0/0 ms

Edge-R1# ping 10.2.2.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.2.2, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 0/0/0 ms

Verification criteria: Both primary (10.1.1.0/30) and backup (10.2.2.0/30) point-to-point transit circuits respond to ICMP echo requests with active Layer 2 ARP resolution.

POS-02: Normal State Routing Table & Path Verification#

On Edge-R1 privileged EXEC mode:

Edge-R1# show ip route static
S*   0.0.0.0/0 [1/0] via 10.1.1.2

On ISP-R2 privileged EXEC mode:

ISP-R2# show ip route static
S    192.168.10.0/24 [1/0] via 10.1.1.1
S    192.168.100.0/24 [1/0] via 10.1.1.1

From PC-1 command prompt:

C:\> ping 203.0.113.10

Pinging 203.0.113.10 with 32 bytes of data:

Reply from 203.0.113.10: bytes=32 time<1ms TTL=126
Reply from 203.0.113.10: bytes=32 time<1ms TTL=126
Reply from 203.0.113.10: bytes=32 time<1ms TTL=126
Reply from 203.0.113.10: bytes=32 time<1ms TTL=126

Ping statistics for 203.0.113.10:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

From PC-1 traceroute:

C:\> tracert 203.0.113.10

Tracing route to 203.0.113.10 over a maximum of 30 hops: 

  1   0 ms      0 ms      0 ms      192.168.10.1
  2   0 ms      0 ms      0 ms      10.1.1.2
  3   0 ms      0 ms      0 ms      203.0.113.10

Trace complete.

Verification criteria: Only primary routes with AD 1 appear in the active routing tables; floating routes with AD 5 remain suppressed/dormant. Forwarding traverses 10.1.1.2.

POS-03: Primary Link Failure and Floating Route Failover#

On Edge-R1, administratively disable the primary WAN link:

Edge-R1(config)# interface GigabitEthernet0/0
Edge-R1(config-if)# shutdown

Inspect show ip route static on Edge-R1:

Edge-R1# show ip route static
S*   0.0.0.0/0 [5/0] via 10.2.2.2

From PC-1 command prompt, verify reachability and trace path:

C:\> ping 203.0.113.10

Pinging 203.0.113.10 with 32 bytes of data:

Reply from 203.0.113.10: bytes=32 time<1ms TTL=126
Reply from 203.0.113.10: bytes=32 time<1ms TTL=126
Reply from 203.0.113.10: bytes=32 time<1ms TTL=126
Reply from 203.0.113.10: bytes=32 time<1ms TTL=126

Ping statistics for 203.0.113.10:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

C:\> tracert 203.0.113.10

Tracing route to 203.0.113.10 over a maximum of 30 hops: 

  1   0 ms      0 ms      0 ms      192.168.10.1
  2   0 ms      0 ms      0 ms      10.2.2.2
  3   0 ms      0 ms      0 ms      203.0.113.10

Trace complete.

Verification criteria: Floating route dynamically installs with AD 5 ([5/0] via 10.2.2.2). Hop 2 in traceroute diverts cleanly from 10.1.1.2 to 10.2.2.2 with zero packet loss.

POS-04: Primary Link Restoration and Preemption#

On Edge-R1, restore the primary WAN link:

Edge-R1(config)# interface GigabitEthernet0/0
Edge-R1(config-if)# no shutdown

Inspect show ip route static on Edge-R1:

Edge-R1# show ip route static
S*   0.0.0.0/0 [1/0] via 10.1.1.2

From PC-1 traceroute:

C:\> tracert 203.0.113.10

Tracing route to 203.0.113.10 over a maximum of 30 hops: 

  1   0 ms      0 ms      0 ms      192.168.10.1
  2   0 ms      0 ms      0 ms      10.1.1.2
  3   0 ms      0 ms      0 ms      203.0.113.10

Trace complete.

Verification criteria: Lower administrative distance (1 < 5) causes immediate preemption of the floating route; traffic automatically returns to the high-speed primary path.

2. Negative Verification (NEG)#

NEG-01: Total WAN Outage (Both Links Down)#

On Edge-R1, shut down both WAN interfaces (GigabitEthernet0/0 and GigabitEthernet0/1):

Edge-R1(config)# interface range GigabitEthernet0/0 - 1
Edge-R1(config-if-range)# shutdown

From PC-1 command prompt, attempt to ping Web-Server:

C:\> ping 203.0.113.10

Pinging 203.0.113.10 with 32 bytes of data:

Reply from 192.168.10.1: Destination host unreachable.
Reply from 192.168.10.1: Destination host unreachable.
Reply from 192.168.10.1: Destination host unreachable.
Reply from 192.168.10.1: Destination host unreachable.

Ping statistics for 203.0.113.10:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

Behavior: With both next hops inaccessible, all static routes are purged from the routing table. Edge-R1 immediately returns ICMP Destination Host Unreachable to client hosts.
Remediation: Restore interface connectivity (no shutdown).

Verification Guide: PTL-0028 Floating Static Routes and Administrative Distance